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<html lang="en"><head><META http-equiv="Content-Type" content="text/html; charset=UTF-8"><link href="../images/docs-stylesheet.css" rel="stylesheet" type="text/css"><title>Apache Tomcat 8 Architecture (8.5.53) - Request Process Flow</title><meta name="author" content="Yoav Shapira"></head><body><div id="wrapper"><header><div id="header"><div><div><div class="logo noPrint"><a href="https://tomcat.apache.org/"><img alt="Tomcat Home" src="../images/tomcat.png"></a></div><div style="height: 1px;"></div><div class="asfLogo noPrint"><a href="https://www.apache.org/" target="_blank"><img src="../images/asf-logo.svg" alt="The Apache Software Foundation" style="width: 266px; height: 83px;"></a></div><h1>Apache Tomcat 8 Architecture</h1><div class="versionInfo">
          Version 8.5.53,
          <time datetime="2020-03-11">Mar 11 2020</time></div><div style="height: 1px;"></div><div style="clear: left;"></div></div></div></div></header><div id="middle"><div><div id="mainLeft" class="noprint"><div><nav><div><h2>Links</h2><ul><li><a href="../index.html">Docs Home</a></li><li><a href="index.html">Architecture Home</a></li><li><a href="https://wiki.apache.org/tomcat/FAQ">FAQ</a></li><li><a href="#comments_section">User Comments</a></li></ul></div><div><h2>Contents</h2><ul><li><a href="index.html">Contents</a></li><li><a href="overview.html">Overview</a></li><li><a href="startup.html">Server Startup</a></li><li><a href="requestProcess.html">Request Process</a></li></ul></div></nav></div></div><div id="mainRight"><div id="content"><h2>Request Process Flow</h2><h3 id="Request_Process_Flow">Request Process Flow</h3><div class="text">

<p>
This page describes the process used by Tomcat to handle
an incoming request.  This process is largely defined by
the Servlet Specification, which outlines the order
of events that must take place.
</p>

<div class="subsection"><h4 id="description">description</h4><div class="text">
<p>
TODO
</p>
</div></div>

<div class="subsection"><h4 id="diagrams">diagrams</h4><div class="text">
<p>
A UML sequence diagram of the request process is available
<a href="requestProcess/request-process.png">here.</a>
</p>
<p>
A UML sequence diagram of the authentication process is available
<a href="requestProcess/authentication-process.png">here.</a>
</p>

</div></div>

<div class="subsection"><h4 id="comments">comments</h4><div class="text">
<p>
The Servlet Specification provides many opportunities for
listening in (using Listeners) or modifying (using Filters)
the request handling process even before the request arrives
at the servlet that will handle it.
</p>

</div></div>

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